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Error code reference

Thermador Range Error Code E:08

WFMC washer

Thermador codesThermador range codes

WFMC washer: Heater doesn't shut off (faulty heater or stuck heater relay).

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What E:08 means on a Thermador range

The E:08 error code on a Thermador WFMC washer indicates that the heater circuit is failing to shut off when commanded. This means the control board has detected that the heating element remains energized beyond its intended cycle, which can lead to overheating of the wash water and potential damage to fabrics, internal components, or the appliance itself. The heater relay on the control board is responsible for switching power to the heating element on and off. When this relay becomes stuck in the closed position, the heater cannot be deactivated regardless of the control signal sent by the main board.

There are two primary hardware culprits for this fault: the heating element itself and the heater relay on the control board. A faulty heating element that has developed an internal short can draw continuous current even when the relay is functioning correctly. More commonly, the heater relay welds shut due to repeated switching under load, a condition where the relay contacts fuse together and cannot open. The control board interprets the continued current flow through the heater circuit as a failure to shut off and triggers the E:08 code.

Diagnosing this fault requires isolating whether the heater element or the relay is the root cause. Checking the heating element for resistance continuity and comparing it against the expected specification can confirm a shorted element. Inspecting the relay on the control board for signs of burning, discoloration, or failed contact separation is also essential. In many cases, replacing only the control board resolves the issue if the relay is confirmed stuck, while a shorted element requires element replacement.

Source: manufacturer service documentation.

Common causes of E:08

  1. 01

    Stuck heater relay on control board

    Part replacement

    The relay that switches the heater on and off has welded its contacts closed, preventing the circuit from opening. This is the most common cause and typically shows as discoloration or burn marks near the relay on the board.

  2. 02

    Shorted heating element

    Part replacement

    The heating element has developed an internal short circuit, causing it to draw continuous current independent of the relay switching state. Resistance testing of the element will reveal an out-of-spec reading.

  3. 03

    Failed control board

    Part replacement

    The main control board may have broader circuit damage beyond a single relay, causing it to incorrectly manage the heater output signal. This can occur alongside a stuck relay or independently due to power surge damage.

  4. 04

    Wiring fault in heater circuit

    Wiring / connection

    A short in the wiring harness between the control board and the heating element can cause unintended current flow that mimics a stuck relay condition. Inspecting the wiring for chafing, pinching, or burn marks can identify this issue.

See the test procedure for each cause

Frequently asked questions about E:08

What does E:08 mean on a Thermador range?
The E:08 code on a Thermador WFMC washer indicates that the heater is not shutting off as commanded during the wash cycle. The appliance has detected continuous heater operation beyond its intended duration. This is typically caused by a stuck heater relay on the control board or a faulty heating element. The washer will halt operation to prevent overheating.
Can I fix the E:08 error myself?
A knowledgeable DIYer can diagnose this fault by testing the heating element for resistance and visually inspecting the control board relay for burn damage. However, replacing the control board or heating element requires disassembly of the appliance and comfort working with electrical components. If you are not confident working with wiring and circuit boards, a qualified technician is recommended.
Is the E:08 error a safety concern?
Yes, this fault represents a real safety concern because a heater that cannot shut off can overheat the wash water and potentially damage the appliance or its surroundings. You should not attempt to run the washer while this error is active. Disconnect power to the unit until the fault has been diagnosed and repaired.
How much does it cost to repair the E:08 error?
Repair costs depend on the failed component. A replacement heating element typically costs between $30 and $80 for the part alone. A replacement control board can range from $100 to $250 or more depending on availability. Adding professional labor, total repair costs commonly fall between $150 and $400 depending on the technician and the specific part required.
Will resetting the washer clear the E:08 error?
A power reset may temporarily clear the error display, but it will not resolve the underlying hardware fault. If the heater relay is stuck or the heating element is shorted, the E:08 code will return as soon as the appliance attempts to heat water again. The faulty component must be repaired or replaced to permanently clear the code.

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